Abstract:
Autistic individuals report high levels of alexithymia, and evidence suggests that alexithymia may cause many challenges related to autism. However, to investigate the impact of alexithymia on the difficulties experienced by autistic individuals, it is essential to reliably and validly measure alexithymia. The present talk describes a study investigating whether the Perth Alexithymia Questionnaire (PAQ) shows good psychometric properties to measure alexithymia in autistic individuals and investigates the impact of alexithymia on anxiety. The study consisted of 298 autistic and 406 non-autistic individuals who completed the PAQ and a trait anxiety questionnaire online. Confirmatory factor analysis and moderated non-linear factor analyses were conducted to investigate measurement invariance (and differential item functioning) and alexithymia differences between autistic and non-autistic individuals. Regression analyses investigated the relationships between alexithymia and anxiety, and whether these relationships are different for autistic or non-autistic populations. Alexithymia manifested similarly in autistic and non-autistic individuals, comprising five factors and a general alexithymia factor. The measure did not meaningfully bias scores for autistic individuals. Autistic individuals reported greater alexithymia across all its components. Alexithymia predicted greater anxiety. However, a negative suppression was found whereby externally oriented thinking reduced anxiety, particularly for autistic individuals, once controlling for difficulties appraising feelings. The findings provide an essential step towards better understanding the emotional processes of autistic individuals by indicating that the PAQ shows adequate psychometric properties in the autistic population. This allows researchers and clinicians to be confident when assessing alexithymia in autistic individuals.